Attachment 7 - Questions and Answers 10 Aug 2020.docx

Remove and Install Trane Chillers for B266 and B1231 Questions and Answers

1. Controls - Will the LRAFB be responsible to unhook the HVAC controls on the existing chillers? SOW states to run EMCS conduit and tie to unit and wrap / tape wires Controls will be removed by the contractor. Contractor shall re-connect the conduit to the controls section of the chiller and leave control wires taped off. Note: manual flow switch on CW line does not have to be connected because the chiller comes with internal flow switch wired into the unit. PWS paragraph 3.2.1.

2. Freon - Does the contractor have to remove the Freon from the (2) removed chillers?

Yes, the contractor shall remove the refrigerant from the chillers. 19 CES HVAC shop will provide the cylinders.

3. Does the existing chilled water systems contain glycol? If so how much?

Yes, the CW system has glycol in it. The chiller has isolation valves which will prevent draining of the system-if isolation function properly. If valves do not operate properly contractor shall be responsible recovery of the CW and pump it back into the system.

4. Will the new systems require glycol? If so what will the required percentage be? Will testing be required?

No, the contractor does not have to put glycol back into the system. It will be brought up to the proper levels by the hydronic water contractor after contract completion.

5. Will all work be required on weekends?

No. It is an option for the contractor to complete the connections if desired. Both chillers have portable units on each system. The contractor should be able to remove and set new chiller and then run the portable. Bldg. 266 will require power to be reconnected to run the portable. Contractor shall coordinate with the 19 CES HVAC shop before disconnect and re-connect of chillers.

6. Who will remove and replace the chain link fencing covering the chiller at B-1231?

19 CES will be responsible for removing the fence over the chiller being replaced at Bldg. 1231. Fence will not be re-installed. PWS paragraph 4.1.

7. Will we need to include controls connection and test out in our proposal or will Trane be taking care of that directly with the AFB?

Chiller will have to be started by Trane for warranty purposes. Start-up will be coordinated between the contractor and the 19 CES HVAC shop before Trane is notified PWS paragraph 3.2.1.

8. Will we need to include any time for start-up?

Chiller will have to be started by Trane for warranty purposes. The chillers were purchased with a factory startup. Contractor will fill out the pre-start worksheet and coordinate with Little Rock Trane to do the startup. PWS paragraph 3.2.1.

9. Will the existing wiring, conduit and breakers be used to serve the new chillers?

Yes, the existing wire and conduit may be used. If it doesn’t reach it is the responsibility of the contractor to extend the conduit and wiring for proper connections in compliance with the electrical code.

10. Should we assume that all butterfly valves are in good working condition and be re-used?

Yes, the existing butterfly valves are available for reuse. If they are defective it is the contractor’s responsibility to replace them. Before chillers are disconnected contractor needs to coordinate with HVAC shop and go over disconnect/reconnect procedures. Any valve reused still falls under the contractors warranty if it fails during the warranty period

11. The specs call for the chilled water valves to be replaced. Does this include the supply and return valves on the permanent chiller and temporary chiller connections? 4 valves per chiller?

The contractor is responsible for replacing the valves. Should the contractor choose to reuse the existing valves, they still fall under the contractor’s warranty.

12. If this is the case, the system will have to be drained and the temporary chiller will not be able to be used. What is the glycol percentage and will contractors be responsible for the loop chemical and glycol?

The contractor is responsible for replacing the valves so the temporary chiller may be used. The replacement of the glycol to the correct percentage is not the responsibility of the installation contractor.

13. It was mentioned during the walk through that there was data center type of equipment in building 1231. How long will we be able to shut down this system without causing a problem? 1231? 266?

Contractor needs to give a two week notice before the work starts at each installation for customer coordination. If an isolation valve change out is needed we will have to make notifications to the customer and work this around the training schedule at building 1231. (Weekend work possible) PWS paragraph 2.1.